When World War I began, she escorted troop convoys from French North Africa to France for a month and a half. Gaulois was ordered to the Dardanelles in November 1914 to guard against a sortie into the Mediterranean by the German battlecruiserSMS Goeben. In 1915, she joined British ships in bombarding Turkish fortifications. She was badly damaged during one such bombardment in March and had to beach herself to avoid sinking. She was refloated and sent to Toulon for permanent repairs. Gaulois returned to the Dardanelles and covered the Allied evacuation in January 1916. On 27 December 1916, she was en route for the Dardanelles after a refit in France when she was torpedoed and sunk by the German submarineUB-47.

The ship used three 4-cylinder vertical triple expansion steam engines, one engine per shaft. They produced 14,420 ihp (10,750 kW) during the ship's sea trials using steam generated by 20 Belleville water-tube boilers. Gaulois reached a top speed of 18.024 knots (33.380 km/h; 20.742 mph) on her trials. She carried a maximum of 1,101 tonnes (1,084 long tons) of coal which allowed her to steam for 3,776 nautical miles (6,993 km; 4,345 mi) at a speed of 10 knots (19 km/h; 12 mph).[1]

The Charlemagne-class ships carried a total of 820.7 tonnes (807.7 long tons)[1] of Harvey armour.[3] They had a complete waterlinearmour belt that was 3.26 metres (10 ft 8 in) high. It tapered from its maximum thickness of 400 mm (15.7 in) to a thickness of 110 mm (4.3 in) at its lower edge. The armoured deck was 55 mm (2.2 in) thick on the flat and was reinforced with an additional 35 mm (1.4 in) plate where it angled downwards to meet the armoured belt. The main turrets were protected by 320 mm (12.6 in) of armour and their roofs were 50 mm (2.0 in) thick. Their barbettes were 270 mm (10.6 in) thick. The outer walls of the casemates for the 138.6-millimetre (5.46 in) guns were 55 mm thick and they were protected by transverse bulkheads 150 mm (5.9 in) thick. The conning tower walls were 326 mm (12.8 in) thick and its roof consisted of 50 mm armour plates. Its communications tube was protected by armour plates 200 mm (7.9 in) thick.[1]

Gaulois, named after the tribes that inhabited France during Roman times,[4] was ordered on 22 January 1895 from the Arsenal de Brest. Her sister shipCharlemagne was being built in the slipway intended for Gaulois so the latter ship's construction was delayed until the former was launched. Gaulois was laid down on 6 January 1896 and launched on 6 October of the same year. She was commissioned on 23 October 1899 after completing her sea trials.[5]

Together with Charlemagne, the ship was assigned to the 1st Battleship Division of the Mediterranean Squadron and they arrived at Toulon in January 1900. Stormy weather during this voyage caused her captain to complain about her forward turret and casemates being flooded out in a head sea. The following month, while exercising in the harbour at Hyères, Gaulois accidentally rammed the destroyerHallebarde, gouging a 4-by-1.5-metre (13.1 by 4.9 ft) hole in the smaller ship. Hallebarde reached Toulon where she was repaired while the battleship was barely damaged. On 18 July, after combined manoeuvres with the Northern Squadron (Escadre du Nord), the ship participated in a naval review conducted by the President of France, Émile Loubet, at Cherbourg. The following year, Gaulois and the Mediterranean Squadron participated in an international naval review by President Loubet in Toulon with ships from Spain, Italy and Russia.[6]

Gaulois at anchor in 1912. Note the large tarpaulin rigged over the quarterdeck to provide shade.

During exercises off Golfe-Juan, Gaulois accidentally rammed the battleship Bouvet on 31 January 1903. Neither ship was seriously damaged in the accident. In April 1904, she was one of the ships that escorted President Loubet during his state visit to Italy. Later that year, the ship made port visits in Thessaloniki and Athens with the rest of the Mediterranean Squadron. A wireless telegraph was installed aboard Gaulois in December 1905. Together with the battleships Iéna and Bouvet, the ship aided survivors of the April 1906 eruption of Mount Vesuvius in Naples. For the rest of the decade, she participated in various exercises with the Mediterranean Squadron and made a number of port visits in France and its dependencies. Gaulois was briefly transferred to the Northern Squadron in August 1910 and she participated in a large naval review by President Armand Fallières off Cap Brun on 4 September 1911. The ship was reassigned to the Mediterranean Squadron in October 1912 and she participated in a naval review by President Raymond Poincaré on 10 June 1913. In June 1914, the Navy planned to assign Gaulois to the Training Division of the Squadron as of October, but this was cancelled upon the outbreak of war in August.[8]

Together with the older French pre-dreadnoughts, the ship's first mission in the war was to escort troop convoys from North Africa to France. Later in September, her main turrets required repairs in Bizerte as the forward turret was having difficulty traversing. Following these repairs, Gaulois was ordered to Tenedos Island, not far from the Gallipoli Peninsula of Turkey, in November to guard against a sortie by the German battlecruiser Goeben. She relieved the battleship Suffren which needed a refit in Toulon. She became flagship of Rear Admiral Émile Guépratte upon her arrival on 15 November. He transferred his flag back to Suffren when she returned on 10 January 1915.[9]

During the bombardment of 19 February, Gaulois supported Suffren as the latter ship bombarded Turkish forts covering the mouth of the Dardanelles. Late in the day, she bombarded the fort at Orhaniye Tepe on the Asiatic side of the strait. During the subsequent bombardment on 25 February, the ship anchored some 6,000 metres (6,600 yd) from the Asiatic shore and engaged the forts at Kum Kale and Cape Helles. Their return fire was heavy enough to force Gaulois to up anchor before she could suppress their guns. Later in the day, she closed to within 3,000 metres (3,300 yd) of the forts and engaged them with her secondary armament. During the day's action, the ship was hit twice, but these did little damage.[10]

On 2 March, the French squadron bombarded targets in the Gulf of Saros, at the base of the Gallipoli Peninsula. Five days later, the French squadron attempted to suppress the Turkish guns while British battleships bombarded the fortifications. Gaulois was hit by a 15-centimetre (5.9 in) shell during this attack that caused little damage as it failed to detonate. Admiral Guépratte and his squadron returned to the Gulf of Saros on 11 March where they again bombarded Turkish fortifications.[11]

They returned to assist in the major attack on the fortifications planned for 18 March. British ships made the initial entry into the Dardanelles, but the French ships passed through them to engage the forts at closer range. Gaulois was hit twice during this bombardment; the first shell struck the quarterdeck, but caused little damage other than deforming the deck. The second shell hit just above the waterline on the starboard bow and did little obvious damage. In reality, however, it pushed in the armour plates below the waterline and opened up a hole 7 metres (23 ft 0 in) by 22 centimetres (8.7 in) through which water flooded in. Little could be done to staunch the inflow and Captain Briard decided to head for the Rabbit Islands, north of Tenedos, where he could beach his ship for temporary repairs. He ordered the non-essential crewmen off the ship in case she foundered en route, but managed to reach the islands, escorted by Charlemagne.[12]

Gaulois was refloated on 22 March and departed for Toulon via Malta three days later, escorted by Suffren. They encountered a storm on 27 March off Cape Matapan and the ship began taking on water as the repairs began to leak under the pressure of the storm. She radioed for assistance later that night and the armoured cruiserJules Ferry and three torpedo boats arrived several hours later. The ship arrived in the Bay of Navarin the following morning and more repairs were made. Gaulois arrived without further incident at Toulon on 16 April and entered drydock the following day. The Navy took the opportunity to increase her stability by lightening her masts, removing some armour from the superstructure and conning tower as well as dismounting two 100 mm and six 47 mm guns. In addition, the ship was fitted with an anti-torpedo bulge that stretched between her bridge and aft superstructure to increase her beam and thus her stability.[13]

Her repairs were completed by early June and Gaulois departed for the Dardanelles on 8 June. She reached Lemnos on 17 June and relieved her sister St Louis on 27 July. The ship anchored 1,000 metres (1,100 yd) off the shore on 11 August to bombarded a Turkish artillery battery at Achi Baba. Splinters from return fire detonated a 100 mm shell and started a small fire, but it was put out without much trouble. On her voyage home, Gaulois ran aground at the harbour entrance and had to unload most of her ammunition before she could be refloated on 21 August. Together with the pre-dreadnought République, the ship covered the Allied evacuation from Gallipoli in January 1916. Badly in need of a refit, she sailed for Brest on 20 August where her captain argued that the range of her main armament needed to be increased by 4,000 metres (4,400 yd) if she was to be considered fit for the battleline. Some thought was given to disarming her and converting her into a barracks ship, but nothing was done before the ship was ordered back to the Eastern Mediterranean on 25 November.[14]

Corbett, Julian (1997). Naval Operations. History of the Great War: Based on Official Documents. II (reprint of the 1929 second ed.). London and Nashville, TN: Imperial War Museum in association with the Battery Press. ISBN1-870423-74-7.